Self sealing tube and process of making the same



Nov. 17, 1931. J. J. MCCALL SELF SEALING TUBE AND PROCESS OF MAKING THE SAME Filed June 2, 1928 I rwe nfor John doaeph Me Call /ber.

Patented Nov. 17, 1 931 UNITED STATES PATENT oFFlcE JOBIN JOSEPH MOO-ALL, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR OF ONE-HALF '10 DAVID N. SAIBAN SELF SEALING TUBE AND PROCESS OF MAKING- ,TH'E SAME Application filed June 2, 1928. Serial No. 282,497.

This invention relates to an improved pneumatic tube, a new plastic composition which may be used therewith and a new method of manufacturing such tube and com- J position.

' The tubes at present in use are defective for the reason that no provision is made for the prevention of blowouts and punctures with the consequent possibility of injury when such an event occurs. 1 Although many attempts have been made.

to solve this problem, yet there are few, if any, tubes on the market at present which have specific provisions to prevent punctures a) or blowouts, or at least reduce the possibility of such occurring. The reason for this condition is found in the cost of manufacture of such tubes, in the character of the composition used, in the difiiculty of manufacture and \J assembly of the component parts, or in any combination of the above causes.

It is the applicants purpose to produce a tube which shall be comparatively easy to manufacture and assemble and to produce a cheap to manufacture, easy to apply and which shall be efficient.

- More particularly stated, one of the purw poses of my invention is to produce a pneu-.

0 matic'tube which shall be self healing in the event of a puncture.

Another object of my invention is to produce a pneumatic tube which shallgreatly obviate the possibility of the occurrence of blowouts and punctures. 1 Another object of my invention is to produce a pneumatic tube having an inner guard.

Another object of my invention is to produce a pneumatic tube having an inner ard which guard shall be separated from t e remaining portion of the tube by an air space.

Another object of my invention is to produce a pneumatic tube having an inner guard which guard shall be separated from the re-' 0 maining portiom of the tube by a filler.

filling composition which shall be easy and Another object of my invention is to dis clciose a method of making the said pneumatic tu e. 1

Another object of my invention is to pro- I will show the composition used in association with my new tube structure, yet it is to be distinctly understood that this is merely the preferred form and by the way of illustration only.

In conjunction with my new tube structure any kind of filling composition, which need not necessarily be the filling composition herein disclosed, may be used. Also, my filling composition may be used with any kind of tube structure which need not necessarily be the same as that herein disclosed. The use of either the composition alone or the tube structure alone is within the scope of my invention. The useof both together as herein shown is at present believed to give the best results; But,- it is realized by the inventor that vthe new composition herein disclosed may be used in conjunction with any type of tube structure, and that the tube structure herein shown may be used either alone or in combination with any kind of filling composition without departing from the scope or spirit of this invention. A

With the above cited and other obj ect's reference is now had to the following disclosure and the drawings to which they refer for the purpose of clearly vbringing out my invention.

In the drawings Figure 1 shows a tube on a mandrel and illustrates the first step in my process of the structure of my tube.

and tube, showing only the tube, and illustrates the second step in the process of constructing my tube.

Figure 3 is a section taken similarly to Figure 2 showing the completed tube while it is still on the mandrel and illustrates the third step in my process of constructing the tu e. I

Figure 4 is a section on the line 44 of Figure 5, and illustrates a sectionof the completed tube after it has been removed from the mandrel and turned to present the proper surface on the outside.

Figure shows a completed from the outside.

Figure 6 is a partial section ofthe tube similar to the lower portion of the tube shown in Figure 4, purposely enlarged for the purpose of more clearly bringing out the structure of the tube.

Referring more particularly to the drawings, reference number 1 shows the completed tube; 2 the outer tube or component of the same; 3 the mandrel upon which the tube is made; 4 a layer of adhesive used to connect the composition .to the outer tube; 5 a filling composition; 6 the ensemble of layers of air and flexible substance interposed between the tube viewed coating composition and the inner guard; 7 s

the inner guard and 12 the air valve.

The outer tube 2 serves the same purpose and considered alone is the same as the ordinary tube .now'in general use.

The filling composition 5 serves as a self acting medium which goes into, or is forced into, the hole caused by a puncture in the tube and serves to fill the gap.

The flexible substance 11 serves to separate the inner guard 7 from the filling composition 5. It further serves to prevent the inner guard 7 from adhering to the filling composition 5. It further serves to help maintain the air space, or spaces, between the filling composition 5 and the inner guard 7. The flexible substance may be paper, as herein shown, or tin foil, or any other substance which has the properties of flexibility, ease of rupture and non-adhesiveness to either the substance of the inner guard 7, the filling composition 5, or both. The flexible substance maybe merely placed between the filling composition 5 and the inner guard 7, but not cemented or otherwise fixedly attached to either, as herein shown, or it may be fixedly attached by cement or otherwise to either the fillingcomposition 5 or the inner guard 7 but not to both. If it is unattached to either, as herein shown. two (2) air spaces 8 are formed. If attached to either the inner guard or the filling composition only one (1) air space is formed. It is my desire and object, however, to always have at least one air space between the filling composition 5 and the inner guard 7.

Ihe inner guard 7 combines with the outer tube 2, the filling composition 5 and the flexible substance 11 to bound and form the air spaces 8. The inner guard further serves as an additional wall to keep the puncturing material from penetrating the tube proper. The inner guard further serves as an additional cover for the punctured surface. The inner guard may be of vulcanized flexible rubber, similar to that composing the outer tube 2, or it may be some other air proof flexible and expandible material.

The inner guard 7 serves to keep the filling composition 5 concentrated at the bottom or tread portion of the tire. Were it not present the pressure of the air in the tube would force the filling composition to spread over the entire inner surface of the tube, thus thinning the same at the tread where it is really needed. The inner guard 7 further serves to keep the composition 5 from direct contact with the upper wall of the tube in the event of a puncture.

The air space or chamber 8 serves to make the action of the filling composition positive.

The air space or chamber 8 further serves as a medium which, by adding a certain thickness to the wall of the tube, serves to keep the puncturing material from penetrating the tube proper. 1

Myprocess of making the tube is as fol lows:

I take an ordinary pneumatic tube of cured or vulcanized rubber made according to any one of the methods now in use, turn it inside out and mount the same upon a mandrel 3; the pneumatic tube constitutes the outer tube 2. I then apply a layer of vulcanizing cement 4 over the entire length and practically half 'the circumference of the outer tube 2. I then apply a'layer of filling composition 5 over the said vulcanizing cement covering the entire length of the tube.

The cement 4 serves as an adhesive to connect the filling composition 5 to the outer tube 2. I then place a layer of paper, or filler, 11 upon the filling composition 5 over the entire length of the tube. The paper layer 11 serves, among other things, to prevent the inner guard from becoming stuck and attached to the filling composition 5. Then at 99, a little beyond the point where the filling composition ends, I apply another coat of vulcanizing cement over the entire length of the tube. I then place thereon the guard in such a manner that the ends 1313 of the guard 7 fall upon the layer of vulcanizing cement at 99, thus joining the inner guard to the outer core at 99. Since the inner guard 7 is only joined to the tube at the points 9-9. the part of the inner guard 7 between the two edges 99 is free to move in relation to the surface of the paper layer 11 and the filling composition 5. The above structure results in air spaces 8 between the filling portion 5, the paper layer 11 and the inner guard 7. The tube is now removed from the mandrel 3 and turned inside out in any one of the methods now well known product shown in Figure 5.

drel.

The above disclosureis to be understood as by the way of illustration only and not by the way of limitation since many variations may be made in the character of the material used and even in the method of assembly of the components without departing from the spirit and scope of my invention. For instance, instead of using a vulcanized .tube which has been removed from the mandrel we can start with the tube as it comes from the vulcanizing process which, although vulcanized or cured, is still upon the man- Instead of placing the paper or its equivalent directly upon the filhngcomposition 5, the same may be inserted between the filling composition 5 and the inner guard 7 after the tube is removed from the mandrel. Instead of using cured rubber for the inner guard, some other equivalent substance may be substituted therefor. Instead of using vulcanizing cement, some other equivalent cement might be used. Or, instead of turning the tube inside out after the coating composition 5, the filler 11 and the inner guard 7 have been attached thereto, the ensemble could be removed from the mandrel without turning the same inside out and the tube finished by inserting the air valve and joining the edges 10 in the manner well known in the art. This would result in a tube having the inner guard 7 as part of the outer wall. A cross section through the finished tube of such a modification would be exactly like Figure 3 of the annexed drawings. Definitiona-The word flexible and expandible material as used in the specification and claims is used to denote broadly flexible vulcanized rubber or any other substance from which pneumatic tubes or the inner guard may be constructed. 7

The words flexible material as used in the specification and claims is used to denote broadly a substance such as paper or tin foil which has the properties of flexibility, ease of rupture and nonadhesiveness to either the substance of the inner guard 7, the filling composition 5, or both. I c 7 Having described a method of constructing my tube and the tube structure, I will now proceed to describe the filler which I use in combination therewith.

I break down smoked sheet rubber and crepe rubber individually, then take seventy for about twenty (20) minutes. Then I add ten 10) pounds of rosin and ten (10) pounds of pitch and continue mixing for ten (10%)- minutes until the desired consistency is o tained.

This results in the filling composition, the components of which are the following ingredients by per cent:

Per cent Rosin 10 Pitch 10 Smoked sheet rubber Crepe rubber 10 The above is to be understood as by the way of illustration only and not by the way of limitation, since slight variations in the percentages of the desired substances may be used without departing from the spirit of my invention, or securing a composition which, in general, has the same qualities and characteristics as those given by the preferred formula.

Having described my invention what I claim as new and useful is:

1. A pneumatic tube comprising in cross section an annular ply of vulcanized rubber, a strip of filling composition directly attached to the said annular ply for a substantial portion of its surface and a strip of flexible and expansible material overlying the said strip of filling composition spaced therefrom and attached at its edges to the said annular ply to divide the said pneumatic tube into a primary air chamber formed by the said flexible and expansible strip and the said annular ply and a permanently sealed'safety air chamber formed by the said filling composition and the said flexible and expansible strip, the said primary air chamber having an inlet valve formed therein. 2. A pneumatic tube comprising in crosssection an annular ply of vulcanized rubber, a strip of filling composition attached to the said annular ply for a substantial portion of its surface, a strip of flexible and expansible material overlying the said strip of filling composition, spaced therefrom and attached at its edges to the said annular ply to divide the said pneumatic tube into a primary air chamber formed by the said flexible and expansible strip and the said annular ply and a permanently sealed safety air chamber formed by the said filling composition and the said flexible and expansible strip, the said primary airchamber having an inlet valve formed therein, and a strip of flexible material interposed between the said filling composition and the said flexibler'and expansible strip. A 4 3." A pneumatic tube comprising in crosssection'an annular ply of flexible and expansible vulcanized rubber, a strip of filling composition attached to the saidannular ply for a substantial portion of its inner surface and a strip of flexible and expansible vulcanized rubber overlying the said strip of filling composition spaced therefrom and attached at its edges to the said annular ply to divide the said pneumatic tube into a primary air chamber formed by the said annular ply and the said flexible and expansible strip and a permanently sealed safe- .ty air chamber formed by the said filling composition and the said flexible and expansible strip, the said primary air chamber having an air inlet valve formed therein.

4. A pneumatic tube comprising in crosssection an annular pl of flexible and expansible vulcanized ru ber, a strip of filling composition attached to the said annular ply for a substantial portion of its surface, a strip of flexible and expansible vulcanized rubber overlying the said strip of filling composition, spaced therefrom and attached at its edges to the said annular ply to divlde the said neumatic tube into a primary air chamber ormed by the said annular ply and the said flexible and ex ansible strip and a permanently sealed sa ety air chamber formed by the said filling composition and the said flexible and expansible strip, the said primary air chamber having an. inlet valve formed therein, and a strip of flexible material interposed between the said filling composition and the said flexible and expansible strip.

5. A pneumatic tube comprising in cross section an annular pl of flexible and expansible vulcanized rubber, a strip of filling composition attached to the said annular ply for a substantial portion ofits surface, a strip of flexible and expansible vulcanized rubber overlyin the said strip of filling composition, space therefrom and attached at its edges to the said annular ply to divide the said pneumatic tube into a primary air chamber formed by the said annular ply and the said flexible and expansible stri and a permanently sealed safety air 0 amber formed by the said filling composition and the said flexible and expansible strip, the said primary air chamber having an inlet valve formed therein and a stri of paper interposed between the said ling composition and the said flexible and expansible strip.

In witness whereof I hereby aflix my hand,

April 30, 1928.

JOHN JOSEPH McOALL 

